There is a great need to determine whether or not there is sufficient perfusion, or blood circulation, in microvessels of a patient. Such microvessels include capillaries, arterioles and venules, which are herein all referred to as capillaries. Adequate microcirculation is vital for the transport of oxygen and other nutrients and the removal of waste. Distinctive microvascular pathologies are associated with different disease states such as in diabetes, hypertension, chronic heart disease, chronic ulcers and sepsis. One promising noninvasive technique is the shining of bright light at tissue and the detection of reflected and scattered light. However, it is found that this technique indicates microcirculation only at shallow depths of no more than about one millimeter below the tissue surface. It is known that circularly polarized light penetrates further into tissue than linearly or unpolarized light, but this has not led to better interrogation of tissue. There is a need for the noninvasive detection of microcirculation at greater depths of a plurality of millimeters, in order to interrogate deeper tissue layers, especially the surface regions of organs. A noninvasive technique that enabled such deeper detection of microcirculation would be of value.